Apparatus for grinding and separating fine materials.



I T. A. EDISON. APPARATUS FOR GRINDING'AND SEPARATING APPLICATION FILED JAN.29, 1903.

PATENTED JAN. 22, 1907.

FINE MATERIALS.

Witnesses IIIVQI IIOI' i 0;, .1. 1;

Attorneys may be supplied or cement rock, as the case may UNITED STATES PATENT orrron.

THOMAS A. EDISON, OF LLEWELLYN PARK, ORANGE, NEW JERSEY. APPARATUS FOR GRl'NDlNG AND SEPARATING FINE MATERIALS.

Specification of Letters Patent.

Patented Jan. 22, 1907.

Application filed. January 29, 1903. Serial No. 140,983.

To all whom it may concern:

Be it known that I, THOMAS A. EDIsON, a citizen of the United States, residing at Llewellyn Park, Orange, in the county of Essex and State of New Jersey, have invented a certain new and useful Improvement in Ap aratus for Grindin and Separating Fine aterials, of which t e following is a description.

My invention relates to improved apparatus for separating and grinding fine materials, and particularly to apparatus for feeding ground material from grinding-rolls to a suitable separating device and for returning the tailings of the separator to the rinding-rolls for re rinding, whereby the atter will always be rnished with the maximum load. of material. When the grinding-rolls are arran ed in a plurality of sets, as is preferable, it ecomes important that each set of rolls shall be furnished at all times with the maximum load of material, and it is necessary that this capacity should be present when one or more of the sets of grinding-rolls are shut down for any purpose.

My improved apparatus is'of such a character that a plurality of sets of grinding-rolls with the maximum load of material at all timeswithout interfering in any way with the shutting down of any one or more of the units for any purpose.

Although the apparatus has been especially designed for use in connection with the manufacture of Portland cement and has been utilized in practice in that special field, yet it will be understood that it may be employed in connection with the separating and grinding of fine materials of any desired character.

In the handling of material in bulk requiring reduction to great fineness it is usual to effect the grinding by a series of operations, so as to secure a product of gradually-decreasing size. For instance, with my Portland-cement plant I first pass the limestone be, between massive independently driven giant rolls and then between a plurality of sets of crushing-rolls, by which the material is reduced to a coarse powdered mass the particles of which vary greatly in size. The crushed material is then deposited in a large stock-house in separate conical piles, and from this stock-house it is withdrawn when needed and mixed in the desired proportions of lime and cement rock to form a a pair of l cement mixture which is deposited in a suitable stoclchouse for the purpose;

From this so-called small-rock stock-house the cement mixture undergoes the treatment contemplated by my present invention.

In carrying my invention into effect I first pass the material from the small-rock stockhouse to a suitable separating apparatus, by which the small proportion of sufficientlyfine particles in the original crushed material will be removed. The coarse tailings from the separator are returned to the grindingrolls, preferably arranged in a plurality of sets, and pass through the same, being for the most part reduced to sufficient fineness for ultimate burning. The ground material from the grinding apparatus is now returned to the separator along with materialpassing directly from the small-rock stock-house, so that the material entering the separator will be composed of a mixture of very fine and coarser particles. I find that by passing the fine particles through the separator concurrently with a very considerable lo ad of co arser 7 particles, preferably in excess of the finer particles, a superior separation is secured, since the coarser particles prevent the fine particles from clotting or aggregating and efiect a more perfect presentation of the fine particles to the effect of the separating me-.

dium, preferably blasts of air. The apparatus for returning he coarse tailings from the separator to the grinding-rolls is of such a character as to carry a bulk of material sufficient at least to supply all of the grindingrolls with the maximum load, the arrangement being such that when any of the grinding-rolls are shut downthe resulting excess of material will be returned to the small-rock stock-house. In this way the grinding app aratus will always be supplied with the maxi mum load of material whether all the grinding-rolls are operating or not. i

My invention can be carried out in connec tion with any suitable separating apparatus, although for the handling of cement mix- .tures I prefer to use a device in whch the separation is effected by air-currents, as I describe in my application for Letters Patent filed January 9, 1903, Serial No. 138,428.

four sets of grinding-rolls, and intermediate come imperfectly subjected to the influence conveyers for carrying the invention into efof the separating device. When any set of fect; Fig. 2, an enlarged diagrammatic view grinding-rolls requires to be stopped for any of the buildings and their contents shown in purpose, the roller-feed 17 or other device is Fig. 1, and Figs. 3 and'4 are detail views. stopped, 1n which case the hopper 14, sup- In all of the views corresponding parts are plying that set of grinding-rolls, continues to 2 represented by the same numerals of refersupply material to the other set. Obviously,

ence. however, the hopper in question will be kept The small-rock stock-house 1 is provided. full by only one-half as much material as that with a hopper-shaped bottom discharging formerly supplied to it, and the surplus Wlll the crushed material onto a conveyer 2. overflow onto the conveyer 12, and thereby Material is supplied to the stock-house in any be returned to the stock-house. In this Way suitable Way. The conveyer 2 leads to a it will be seen that any number of grindinghopper 3, supplied with a roller-feed 4, by rolls may be employed and that any of the means of which the material may be fed to grinding-rolls may be stopped Without affectthe separator in a very thin Wide stream. mg in any way the supply of the maximum he separator shown is'of the type described load of material to the other grinding-rolls.

in my said application and comprises a set- What I claim is tling-chamber 5, having a hop per-like bot- 1. Apparatus for separating and grinding tom, a fan 6, discharging through a flue 7 and material in bulk, comprising in combination supplied with air byone or more conduits 8, a stock-house for containing the material in leading from the top of the settling-chamber, bulk, a separator which includes means for and deflecting boards orpartitions 9 in the separately recovering the finer particles, a flue 7, over which the material passes in a ziggrinding apparatus, means for conveying the zag course While being subjected to the airtailings from the separator to the grinding 9o currents. The sufiiciently-fine particles sepapparatus, and means for conveying matearated by the air-blast are carried into the rial from both the stock-house and grinding settlin -chamber 5, deposited in the bottom apparatus to the separator, substantially as thereof by their weight, and are carried oif by set forth. a conveyer 10 to a suitable chalk stock- 2. Apparatus for separating and grinding 5 house. The heavy coarser tailings not infiu material in bulk, comprising in combination enced by the blast pass into a hopper 11 and a stock-house for containing the material in from the latter are deposited on a conveyer bulk, a separator which includes means for 12, leading at its farther end into the top of separately recovering the finer particles, a the stock-house 1. Intermediate of its grinding apparatus, means for conveying the mo length the upper run of the conveyer passes tailings from the separator to the grinding over the idlers 13 and deposits material into a apparatus, meansfor returning to the stockhopper 14:. From the hopper 14 the matehouse the tailings from the separator in eX- rial passes into chutes 15 of grinding-rolls 16, cess of the capacity of the grinding apparathe latter being of any suitable type. At the .tus, and means for conveying material from 10 5 bottom of the chutes 15 I provide a roller-feed both the stock-house and grinding ap aratus 17 or other device for the purpose, by means to the separator, substantially as set orth. of which the material rom the chutes will 3. Apparatus'for separating and grinding be uniformly fed to the grinding-rolls. The vmaterial in bulk, comprising in combinahopper 14 is of any suitable type and stradtion a stock-house for containing the material I 10 dles the conveyer (see Fig. 3) in order that in bulk, a separator which includes means the latter may run over the idlers 13 to perfor separately recovering the finer particles, mit of a deposit of the material in the hopper. agrinding apparatus, a conveyer connecting In operatlon material from the stock-house the tailings-discharge of the separator with 1s fed by the conveyer 2 to the separator, and the stock-house for returning the tailings 1 I 5 within the latter the sufiiciently-fine partifrom the separator to the stock-house, cles are removed and carried off by the conmeans for removing material from the tailveyer 10. The coarse tailings from the sepaings-conveyer to the grinding apparatus, and rator are carried by the conveyer 12 and are means for conveying material from both the supplied to the grinding-rolls 16, any surplus stock-house and grinding apparatus to the beingreturned to the stock-house. The grindseparator, substantially as set forth. mg-rolls reduce the coarse tailings for the 4. Apparatus for separating and grinding greater part to the fineness desired, and this material in bulk, comprising in combination ground material is deposited on the conveyer a stock-house for receiving the material in 2 alongwith materialfrom the stock-house, so bulk, a separating apparatus, a conveyer 12 5 that in consequence the ground material will connecting the bottom of the stock-house be mixed with coarser particles, so as to facili- I with the separating apparatus for supplying tate the separating operation, as I have dematerial to the separating apparatus, a conscribed, by preventing the finer particles from l veyer connecting the tailings-discharge of clotting or aggregating together to thereby bel the separating apparatus with the top of the 1 0 stock-house, a plurality of grinding apparatus, and means for deflecting material the tailings-conveyer to ratus, substantially as and for the purposes set forth.

5 Apparatus for separating and grinding material in bulk, comprising in combination a stock-house for receiving the material in bulk, a separating apparatus, a conyeyer connecting the bottom of the stock-house with the separating apparatus for supplying material to the separating apparatus, a con veyer connecting the tailings-discharge of the separating a aratus with the top of the stock-house, a p urality of grinding apparatus, means for deflecting material from the tailings-conveyer to the grinding apparatus, and connections between the grinding apparatus and the first conveyer for returning material to the separator, substantially as and for the purposes set forth.

from tion with the grinding' appa- 6. In a grinding apparatus, the combinathe material to be ground, and a plurality of sets of grinding-rolls, of means for conveying from the bottom of the receptacle a suflicient bulk of material to furnish all of the sets of grinding rolls with the maximum load, means for deflecting the material to the several sets of grinding-rolls, means for returning to the top of the receptacle any surplus material in excess of the capacity of the grinding-rolls, and an independent feed for each of the grinding-rolls arranged to stop the feed of material to any set when desired, 5 substantially as and for the purposes set forth. This specification signed and witnessed this 22d day of January, 1903. THOMAS A. EDISON. Witnesses:

J. F. RANDOLPH, FRANK L. DYER.

a suitable receptacle for receiving 3 

